Aerial propeller.



W. S. & A. H. BARROWS.

AERIAL PROPELLER.

APPLICATION FILED MAR.24, 1913.

1,144,521. Patented June 29, 1915.

. TED strains Parana cr me/u.

WILBER S. BARROWS AND ASAHEL H. IBARROWS, 0F CHTCAGO, ILLINOIS.

AERIAL PROIELLER.

Application filed March 24, 1913. Serial No. 756,304.

To all whom it may concern Be it known that we, WILBER S. Barrows andAsnnnr. l-I. BARROWS, citizens of the United States, residing atChicago, Cook county, Illinois, have invented certain new and usefulImprovements in Aerial Propellers, of which the following is aspecification. Our invention relates to aerial navigation, and hasparticular reference to the construction of propellers for aeroplanes.

The object of the invention is to. provide improvements in the propellerto the end of adjusting its pitch, even during flight, to-

the atmospheric conditions and the acquired speed of the aeroplane onceit is in motion. Another object of the inventionis to provide adjustableaeroplane propeller blades so that propellers arranged tandem may havethe pitch of their, respective blades adjusted with respect to therelative air currents that they encounter, and in view of the factthatthe rear of a tandem pair of propellers must operate u on a current ofair set in motion by the orward propeller of the pair.

Other subsidiary objects of the invention will appear from the detaildescription of the invention, which consists in the novel construction,combination and arrangement of parts, hereinafter described, illustratedin the accompanying drawing and incorporated in the appended claims.

In the drawing, Figure 1 is'a sideviewpf one of the propeller blades,together w1th its axial mounting and portions of the re mainder of thepropeller. Thisview also shows sectionsof the companion bladeson thesame shaft for the arrangement shown in Fig. 5.. Fig. 2 is a view takenon a vertical plane at right angles to the vertical plane of Fig. 1 andrepresents a tandem pair of propellerson the same shaft, as in Fig. 5,v

parts being broken away, and-also the adjusting mechanism to vary thepitch of the blades. 7 Fig. 3 is a section taken substantially on theline 3-3 of Fig. 2. Fig. 4 is a reduced diagrammatic view showing thedifference in pitch between the blades of, respectively, a forward and arear propeller arranged tandem on a single shaft. Fig. 5 is aperspective view showing on a reduced scale a tandem pair ofpropellers'to beadjusted in accordance with the means provided for suchadjustment shown in the larger views. Fig. 6 is a diagrammatic viewshowing the theoretical eflect upon-the air slot 12 in the sleeve,

of a propeller having blades arranged in the usual way, or extending ontrue radial lines from their axes of rotation. Fig. 7 is a diagrammaticview representing the relative effect of the present arrangement ofpropeller blades upon the air-currents encoun and 4 while the blades ofthe propeller at the opposite end are labeled 5 and 6. Each propellerblade or Wing is mounted to turn on its longitudinal axis and forthat.purpose is provided with a journal or socket portion, this portionfor the blade 3 being represented as 7 "and that for the blade 4 as 8.The n'opeller having blades 5 and 6 is identically constructed. Thejournals 7 and 8 are mounted in a pair of parallel sockets in thepropeller hub 9 keyed to the shaft 2, and these sockets are arranged onopposite sides of the shaft 2 which disposes the axes of the bladestangentially to the circular path of the propeller, as shown mostclearly in Fig. 1. The mechanism for rotating the propeller blades ofeither one propeller or both of them together is represented by a sleeveslidably mounted on the-shaft 2 and caused to rotate with said shaft bymeans of a pin or stud 11 which is fixed in and projects at right anglesfrom the shaft into a which permits its slid mg ,movement. In Fig. 2this sleeve is shown connected with the four blades of the twopropellers, but it .is equally adapted for operating the blades of asingle propeller by simply disregarding the connections at one of-theends of said sleeve. On the ends of the sleeve areshrunk, or otherwisesuitably secured,-ball-bearings 13, 14, 15 and 16. The bearing-member 14of the pair of members at one end of the sleeve, is secured to thesleeve and rotateswith it, whileits companion member 13 is stationary.The same is true of the members 15 and 16 where the member 15 rotateswith the sleeve and-tho member 16 is stationary. Balls 17, provided withthe usual ball-races, are inserted between the respective pairs ofbearing-members. The stationary members 13 and 16 areyoked. together, orconnected, by a rod 18 which has threaded engagement with apertured andthreaded ears 19 and 20 on way as, for instance,

the members 13 and 16, respectively. To the extreme ends of the sleeve10 are secured two oppositely disposed pairs of ears, the pair at theleft end being designated as 2l'and 22 and the pair at the opposite end,of which only one is disclosed in Fig. 2, as 23. 21 and 22 may beregarded as a side elevation of 23, and 23 an end view of 21 and 22, theone pair of ears being arranged at right angles to the other pair. Theinner ends of the blades of each propeller are, laterally of their axesor swivel joints in the hub, connected withthe sleeve 10 by means ofrods 24 and-25 which are linked to the ears 21 and 22 on the sleeve andears 26 and 27 on bars or levers such as 26 in Fig. l adjustably securedin any suitable by means of bolts 26 which engage holes 27 which passthrough the lever and blade. Referring to the ear or eye 26, by shiftingthe bolts 26" into different holes 27 26 may be removed farther.

away from the axis of the blade. Thus a given thrust or pull movement inthe rod 2% will, .when the lever is lengthened, produce a smallerturning movement in the blade than when the eye 26 is nearer the axis.By means of this adjustment the blades of one propeller may be set at apitch different from the pitch of the other pro-' peller blades on thesame shaft by making the levers 26 longer on the one set of blades thanon the other. The connecting-rods themselves are made variable in lengthby making them in two sections connected by a turn-buckle 28. In Fig. 4the propeller blades 5 and 6 represent the rear of a tandem pair and arethere shown set at a greater pitch. than the pitch of the blades 3 and4.

29 represents a suitable strap, cord or other connection secured at 30to the sleeve in motion relative to the machine.

10, leading toa suitable lever or other control (not shown) at the usualoperators seat, by means of which the sleeve may be moved to and fro onthe shaft to vary the pitch of the blades 3 and t where only onepropeller is used, or blades 3 and 4c and 5 and 6 where the propellersare arranged tandemas in the drawing. By changing the inclination orpitch of the propeller blades the speed of the machine may be varied.Again, when the machine is in motion the blades of the propellers, whenset at a fixed pitch, do not obtain the same hold upon the air that theydo when the machine is standing still. In the one case the blades takehold of a comparatively still atmosphere while in the other theatmosphere is If the pitch of the blades can be changed to adjust themtothe change from the relatively still to the relatively moving air, theinitial grip,

which must be comparatively powerful to start the machine, may bemaintained to a large extent after the machine is under way, orinflight. As the rear blades of a tan' dem pair of propellers must takehold of air in greater motion than that which the forward blades mustoperate in, by reason of the rearward current set in motion by theforward blades,"the differential adjustment provided by the turnbuckles28 is provided so as to enable the operator to set the relative pitch ofthe rear blades accordingly.

With reference to the mounting of the axes of the blades on oppositesides of the axis of-rotation of the propeller as a whole, Figs. 6 and 7show the theoretical efl'ect of this change from the usual radialarrangementof the blades shown in Fig. 6. In these figures 31 representsparallel arrows or a given direction of current, while 32 and 33represent radially extending propeller blades and 34 and 35 thetangentially arcurrent direction at an obtuse angle with reference tothe axis of the propeller which tends to scoop in or condense the air infront of the propeller instead of dissipating or rarefying the airoutwardly, thus giving the tangent blades a firmer body of air to takehold of. 38 in Fig. 6 represents the theoretical greater density of airatthe outer circle of the propellers circle of movement at the expenseof air drawn from the center. If, on the other hand, the air is drawninwardly in the direction of arrows 37 the surrounding air-supply willbe'drawn upon to make the air in the path of the propeller denser. 1

The construction of the blades 3 to 6 is shown in the drawing adaptedfor the use of light metal such as aluminum for the body of the blade,said bddy being strengthened by a rib 39 made oftubing splitlongitudinally and secured to one side of the blade in any suitablemanner. The journal portions 7 and 8 may be projecting undividedportions (or circular instead of semicircular in cross section) of thetubing 39 or stiffening rib. As shown the outer end tions between saidlevers and said member, nal portion mounted in the journal bearing,means forvarying the lengths of said cona longitudinall adjustable levermounted nections, and means for varying the length on each rope er bladeat right angles to of throw of said levers. its axis 0 rotation on itsjournal, and means 5 2. The combination with a propeller, of a forswinging said lever to vary the pitch of 20 hub for the blades of saidpropeller, jourthe blade. nals on said blades, bearings in said hub forIn testimony whereof we have hereunto said journals, means for turningsaid blades 'set our hands in the presence of two subin said bearings,and means for varyin the scribing witnesses.

10 lever connections to varv the extent 0 the a, i

turning movement of saill blades. 3. In a propeller, the combinationwith i the blades of said ropeller, of a hub having Witnesses: journalbearings t erein, a stifiening rib for MAE C. ALLEN,

,15 each of said blades, said rib having a jour- J. W. BEcKsTRoM.

